MFG - Manufacturer Specific codes, which have a '1' as their second digit to indicate they are unique to a particular vehicle make or model. These special codes were deemed necessary by the vehicle manufacturers so they could provide additional diagnostic information beyond the basic list of generic OBD II codes for all kinds of faults, not just emissions-related faults.

How To Fix C1666 ?

The valves of each cylinder are kept closed using a pair of arms that replace the conventional engine's roller-type rocker arm. C1666 code one of these arms follows the cam profile while the second arm connects to the valves. During normal engine operation the two arms are joined by a locking pin.

C1666 Code Description:

The oxygen (02) sensors on your car measure the oxygen in the exhaust to determine how rich or lean the ratio of fuel and air are in the cylinders. Optimizing this mixture means better fuel economy and fewer exhaust emissions. When you see C1666 engine fault code on your engine code reader this description will help you.

Final Step:
In the definitions listed below, there is a test drive recommended after you've completed any repairs to see if the condition is fixed. Before you take a test drive after a repair, always erase the C Code(s) first. This will turn the check engine light off and then you will know if the check engine light returns, you've got further diagnostics to complete.

BE CAREFUL !
This engine code information is presented for information purposes only. This is not intended as repair advice and we are not responsible for any actions you take on any vehicle.